Stoves



1955 A. A. SMITH ET AL 2,715,398

STOVES Filed June 29, 1950 2 Sheets-Sheet l FIG. 4

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STOVES Filed June 29, 1950 2 Sheets-Sheet 2 ARTHUR. ASMITH.

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2,715,398 Patented Aug. 16, 1955 STOVES Arthur A. Smith and Max Smith, Winnipeg, Manitoba, Canada Application June 29, 1950, Serial No. 170,972

1 Claim. (Cl. 126-73) This invention relates to improvements in stoves and an object of the invention is to provide a stove for the burning of lignite and to provide a stove of this character which will break up the carbon from the soft coal by mixing pure air, thereby creating carbonic acid gas to furnish an intense heat in the combustion chamber.

Yet another object of the invention is to provide a heater which will not become extinguished when checked.

Still another object of the invention is to provide a device of the character herewithin described which includes a rear draft intake between the hopper and the combustion chamber of the furnace and communicating with the fire-box.

With the foregoing more important objects in view, and such other objects as may appear as the specification proceeds, the invention consists primarily in the arrangement and construction of parts, all as hereinafter more particularly described, reference being had to the accompanying drawings in which:

Figure 1 is a perspective view of the stove.

Figure 2 is an enlarged perspective view of the apertured plate in the rear draft intake, reversed as to Figure 1.

Figure 3 is a fragmentary side elevation of the lower portion of the stove sectioned in part to show the interior thereof.

Figure 4 is an enlarged fragmentary side elevation of the apertured plate in situ.

In the drawings like characters of reference indicate corresponding parts in the different figures.

The invention consists of a fire-box 1 of the configuration shown, this fire-box being provided with a number of parallel vertical ribs 2 and legs 3 which may be nickeled to add to the appearance of the unit.

Upon each of the side Walls 4 of the fire-box is a bracket 5 provided with an upstanding lug 6. These brackets support a horizontally laid grate 7. A further grate 8 provided with a bevelled lower edge 9, lies obliquely within the fire-box with its upper end resting against the front face and the bevelled portion 9 bearing against the upper end of the upstanding lug 6.

Upon the front face 10 of the fire-box is provided a front draft assembly collectively designated 11 which includes a collared aperture 12 communicating with the interior of the fire-box, and to which is hingedly secured an adjustably apertured plate 13, the hinges 14 being situated at the upper edge thereof so that the plate 13 normally resides in the lowermost or closed position as illustrated in Figure 1.

Plate 13 is provided with adjustable apertures 14 and a slide plate 15 whereby the dimensions of said apertures may be varied thus varying the amount of air drawn therethrough.

The top of the fire-box is open, being provided if desired, with a narrow flange (not illustrated) extending around the upper periphery thereof. Situated over the forward portion of the fire-box is a coal feeding hopper collectively designated 16 which is suitably bolted to the fire-box by means of bolts 17.

This hopper is provided with an aperture within the upper surface 18 thereof, over which a hinged lid 19 is positioned and which may be used for charging the hopper as desired. The lower side walls 20 of the hopper converge downwardly and inwardly to the fire-box to facilitate the transference thereto of coal contained within the hopper as will hereinafter be described.

Secured over the rear portion 21 of the fire-box and in spaced relationship from the aforementioned hopper 16, is provided an enlarged combustion chamber 22 suitably ribbed as at 23 to facilitate the transference of heat therefrom to the surrounding atmosphere, said combustion chamber being bolted to the upper edges of the fire-box in a similar manner to the aforementioned hopper 16.

The upper end 23 of the combustion chamber is provided with an aperture 24 having an encircling flange 25 to which may be attached conventional flue pipe sections.

What is defined as a rear draft intake collectively designated 26 is provided upon the fire-box 1 and between the aforementioned hopper 16 and the combustion chamber 22. This intake includes a plate 27 spanning the upper edges 28 of the fire-box and having an external configuration to conform with the front lower surface 29 of the combustion chamber and the rear lower surface 39 of the hopper.

Reference to Figure 2 of the accompanying drawings will show the preferred construction of this plate which is substantially rectangular in section and which includes a plurality of apertures 31 extending therethrough thereby communicating with the interior of the fire-box and permitting air to pass downwardly thereinto.

Elongated open-ended slots 32 are provided at the ends 33 of the plate through which bolts 34 extend and are screw-threadably engageable with the aforementioned upper sides 28 of the fire-box 1 thereof.

An upstanding rib 34 is preferably formed integral with plate 27 and is situated substantially towards the front edge 35 of the plate as clearly illustrated in Figure 2. This rib extends upwardly at right angles from the surface 36 of the plate and is provided with an elongated slot 36 engageable by a lug 37 extending outwardly from the front wall 38 of the hopper 16.

A bolt 38 passes through an aperture 39 in the lugs rearward of the rib 34' and is screw-threada'oly engageable with a boss 39 formed upon the upper surface 36 of the plate.

The combination of the open-ended elongated slots 32 and the elongated slot 36 together with bolts 34 and lug 37 provide mechanical means to permit expansion and contraction of the plate 33 with relation to the fire-box 1 thus preventing any undesirable stresses to be transmitted to said fire-box.

The provision of rib 34 engageable by lug 37 as hereinbefore described prevents torsional distortion of plate 33, as it will be appreciated that an extremely high temperature is present below and around said plate when the stove is in operation and that if means were not provided to counteract this distortion, the plate would become severely damaged or would break the fire-box walls.

It has been found, in this connection, that if the plate is manufactured from a cast steel containing a percentage of chromium any burning or distortion thereof is materially reduced.

Means for thermostatically controlling the raising or lowering of the front draft door 13 is provided and includes a bi-metallic thermostat unit 40 situated between the aforementioned combustion chamber 22 and the hopper 18. A rod 41 mounted for rotation within brackets 42 spans the upper surface of the hopper and is provided with an angulatedend'43 from which extends a chain 44 to the aforementioned draft; door 13.

A dial adjustment (not illustrated) of conventional structure is also included within the thermostat unit 40 for setting the limits between which same actuates.

In operation, the hopper 16 willbe filled with soft co'al which will rest upon the grate 7 and fall over 'into the rear portion of the fire-box 1. The fuel is now ignited and the fire will extend into'the' combustion chamber 22, the coal in the hopper falling into the fire zone on or over the grate 7 to be ignited by the intense heat within the fire. The intensely hot gases within the fire-box proce'e'ding upwardly through the combustion chamber will draw air downwardly through the rear draft passageway between the combustion chamber and the hopper, said air entering through the aforementioned apertured plate 33. In this way, fresh air will mix with the gases from the soft coal to create carbonic acid gas which will further' intensify the heat Within the fire zone.

To stimulate the draft further, if desired, the aforementioned plate 15' situated uponthe front draft door 13 may be adjusted by sliding to the left or right to cover or uncover the apertures 14'.

Due to combustion being so perfect, the amount of soot and ashes which are left in the Stove and connecting pipes, is negligible. An additional advantage is that due to the large oval radiating surface and the ribbing upon the combustion chamber, the intense heat in the rising gases within the combustion chamber is practically all radiated before the gases proceed through the aper' ture 24 and into the fiue pipes (not illustrated).

The aforementioned dialadjustment should be set so that when the temperature within the area between the hopper 16 and the combustion chamber 22 reaches a predetermined figure, the thermostat unit 40 expands or contracts thereby raising or lowering the aforementioned draft door 13 thereby regulating the action of the stove.

Finally, it should be mentioned that it is desirable to make the stove preferably ofcast iron to withstand'satisfactorily the intense heat imposed upon it and also to Withstand the results of abuse such as its being left with all the drafts open for an unnecessarily long period.

Since various modifications can be made in the invention as hereinabove described, and many apparently widely different embodiments of same made within the spirit and scope of the claim Without departing from such spirit and scope, it is intendedthat all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

What we claim as our invention: 7

An apertured plate for rear draft intakes of self-feeding hopper type furnaces situated between the hopper and combustion chambers thereof, said plate adapted to span the outer edges of the side Walls of the associated fire box, said plate being substantially rectangular when viewed in plan and having the rear edge thereof concave,

an arcuate upstanding rib spanning substantially the width of said plate and situated towards the front edge thereof, the depth of said rib increasing from each end towards the centre thereof, means to control'the heat-change-in duced' torsional distortion of said plate, said means including an elongated slot adjacent the centre of said rib whereby said plate is adapted to engage an associated lug extending rearwardly from the rear wall of said hopper and to be suspended" therefrom.

References Cited in the file of this patent 

